In the reaction, represented by, 2SO2 + O2 ⇋ 2SO3; ΔH = -42 kcal; the forward reaction will be favoured by

Answer: Option C

Le Chatelier's principle says that for an exothermic reaction decrease in temperature favours the forward reaction and for a reaction if $$\Delta n<0$$   the increase in pressure favours the forward reaction and for a reaction if $$\Delta n>0$$   the increase in pressure favours the backward reaction. Since the given reaction is having $$\Delta n<0$$   increase in pressure favours the forward reaction.